1. Field of the Invention
This invention relates to reflector antenna radomes. More particularly, the invention relates to a reflector antenna radome with a backlobe suppression ring around the radome periphery.
2. Description of Related Art
The front to back (F/B) ratio of a reflector antenna indicates the proportion of the maximum antenna signal that is radiated in any backward directions relative to the main beam, across the operating band. Rearward signal patterns, also known as backlobes, are generated by edge diffraction occurring at the periphery of the reflector dish. Where significant backlobes are generated, signal interference with other RF systems may occur and overall antenna efficiency is reduced. Local and international standards groups have defined acceptable F/B ratios for various RF operating frequency bands.
Prior reflector antennas have used a range of different solutions to maintain an acceptable F/B ratio. For example, conical RF shields which extend forward of the reflector may be applied. However, shield structures increase the overall size, wind load and thereby structural requirements of the antenna, increasing overall antenna and antenna support structure costs. Edge profiling, chokes and or reflector edge notching/serration patterns have been formed in and or applied to the reflector dish periphery. However, these structures, in addition to significantly increasing the manufacturing costs of the resulting antenna, increase antenna wind loading and are typically optimized for a specific frequency band which limits the available market segments for each specific reflector dish design, decreasing manufacturing efficiencies.
F/B ratio is especially significant in modern shield less deep dish reflectors. Deep dish reflectors, by having a low focal length to reflector dish diameter ratio, may be formed with increased aperture efficiency and low side lobes without requiring peripheral shielding. However, to achieve these radiation patterns, the edges of the deep dish reflectors are designed to have higher signal illumination levels relative to shallow dish designs, increasing reflector edge diffraction and thereby generating significant backlobes.
Competition within the reflector antenna industry has focused attention on RF signal pattern optimization, structural integrity, as well as materials and manufacturing operations costs. Also, increased manufacturing efficiencies, via standardized reflector antenna components usable in configurations adaptable for multiple frequency bands is a growing consideration in the reflector antenna market.
Therefore, it is an object of the invention to provide an apparatus that overcomes deficiencies in the prior art.